hey Frank I disagree with you here because I think you are neglecting one major aspect to generosity. There is a cost associated with generosity despite what some might try to claim, there is. The part you are missing is that any time you exercise generosity you are actually giving up something, like time, labor, money, space, ect.
Now that might seem obvious, but what you are trying to insist when you say;
"I think you need some lessons in what it means to actually help others, including your friend and that it's not always convenient."
You are basically saying that he is obligated to make a sacrifice of time, labor, space to his friend. That one should always accommodate a friend when ever they need it. But that is not the healthy thing to do, sure it might be thoughtful or admirable but it is not always healthy to always make sacrifices for others. When you give too much, you can leave yourself short of what you need for yourself and that can cause problems that are unnecessary.
He clearly pointed out why he couldn't accommodate his friend and he was specifically saying the cost was too high. He needed this time for recouping and if he isn't able to have this time, it might cause problems for him later. It is a legitimate self concern and one I think some extremely generous people often neglect to consider until they find they have spent all their ability and they wind up in their own problems.
There is absolutely nothing wrong with weighing the costs for being generous and then making the decision of weather or not you are willing to. You should never feel obligated to help someone because you call them a friend.